An energy-taking circuit of a two-level inverter and its start-up control method

Abstract

The invention provides two-level inverter energy-taking circuits; the number of the circuits is 2n, and the circuits are connected in parallel with a two-level inverter power device; the energy-taking circuit comprises a capacitor and a second diode connected in series; the anode of the second diode is connected with a collector electrode of the power device, and the cathode of the second diode is connected with an emitter electrode of the power device through the capacitor; a two-level inverter energy-taking circuit start control method comprises the following steps: 1, setting a first trigger signal and a second trigger signal of the two-level inverter; 2, using the first and second trigger signals to trigger the two-level inverter, and outputting a PWM control signal to the two-level inverter after triggering, thus starting the two-level inverter to normal work. Compared with the prior art, the two-level inverter energy-taking circuit and start control method thereof can alleviate current bearing ability of a power module and the energy-taking circuit, thus effectively protecting the power module and the energy taking circuit.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an energy harvesting circuit of a two-level inverter and a start-up control method thereof. Background technique [0002] At present, flexible DC transmission uses IGBT device converter valves, and there are three main topologies: three-phase two-level commutation topology, modular multi-level commutation topology (MMC) and cascaded two-level commutation topology. Three-phase two-level topology is the most widely used voltage source converter topology in engineering. Modular multi-level topology can output output voltage waveform with high waveform quality, enhanced topology flexibility, cascaded two-level converter The topology is similar to the modular multi-level converter topology in structure, that is, its bridge arm is mainly composed of multiple two-level converter sub-modules with the same structure connected in series. Module selectable voltage levels. The im...

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Problems solved by technology

However, in high-voltage applications, there are problems such as external insulation and structural installation, and the volume and cost of the equipment are large, so it is generally used in relatively low-voltage applications.

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